Neumann small format console mod

[beatnik]

I have bought this old Neumann 8x2 mixer, seventies made i think
I am still waiting for the delivery, so I don't know yet how the desk is exactly configured.
Please note that - sadly - the eq modules had been removed and sold prior to my purchase.

The main channels have 8x PV-46-B modules.
There are other 5 line modules nearer the master section, but I can't understand what they are. I suspect PV-15 but I'm not sure.
One thing I'm afraid is that this desk might be commissioned from a broadcast station, so probably the output level is not optimal for interfacing with other equipment ??

First thing I'm planning to do,  adding as much line inputs as can fit in the frame.
But I am already a bit confused because there are 3 different versions of the PV-46 line amp !

- PV-46-B  present in the consol are actually called "compensation amplifier" on the schematic

- PV-46-SD is very similar to the B version but there is some small changes in the circuit

- PV-46-D is the latest version, it's dual channel, uses different transformers and runs OA10 discrete opamps instead of plain transistors as the B and SD versions

I already have a spare PV-46-D module and have opportunity to buy a few PV-46-SD. The only thing I'm concerned about, is because the other channels in the console are using PV-46-B modules, there could be any compatibility issues regarding impedance and levels mismatch between the different versions ?
If this is not the case, it would be great, different sounding channels could be useful to differentiate separate tracks / stems

After I'll have sorted out the configuration of the channels, will think about adding a couple of aux channels, headphone amp, some switching, etc..

Looking forward to getting all kinds of ideas and recommendations for this project !!

All the best fellas

 

[beatnik]

Schematics for all the modules mentioned above are in the Technical Documents section, scroll to page 4

http://groupdiy.com/index.php?topic=44805.60

 

[beatnik]

Here is a picture of the desk that shows the line amp modules

 

[beatnik]

PSU

 

[beatnik]

these are the technical documents for a larger format console from the same period

https://www.dropbox.com/s/0fpbjp9a4fm29sh/Neumann%2069%20console.pdf?dl=0

 

[beatnik]

Miscellaneous data and schematics

https://www.dropbox.com/s/di9pft4fzjhatxc/Neumann%20Components%201967.pdf?dl=0

 

[beatnik]

1966 catalog with mix of information and nice pictures

https://www.dropbox.com/s/k312ol631hwqlew/Gotham-Audio-1966.CV01.pdf?dl=0

 

[Gold]

The PV-46-D with the OA10's is from a later era than that console. As long as Input, Output and Power are in the right place it could work. 

All the discrete PV-46 versions should be interchangeable. Some PV-46 don't have level pots on them. Often there are trimmers on the mating connector in this case. You would run into problems putting one with a pot into a slot where there is a pot or gain set resistor on the mating connector.

The smaller cards are either PV15 or PV26.

The console looks complete to me except for the PEV's. It looks similar to the SP66 cutting console I have. In the SP66 the PEV's serve as the Line Input as well as the EQ. The PV46's are used as gain makeup for attenuators. The PV15's are Line Out.

I haven't found a Line Input card from the same era with a transformer input and an unbalanced output. You could use PV-46's as Line In if PEV's are too expensive and hard to find.

 

[gyraf]

Now THAT is a real console! The 69 model even has a cigarette lighter module (pdf p.45) !!!

Thanks for posting these...

If you run into problems sourcing specific parts/modules, let me know - I may have some modules from a similar console I got once in cut-up shape.

Jakob E.

 

[beatnik]

Now THAT is a real console! The 69 model even has a cigarette lighter module (pdf p.45) !!!

Yes!!! And it was even made by Rolls Royce  !!!!  When I saw that I got the feeling I should trash away all the rest of my equipment !!!

Jacob, it's always great to know there is opportunity to buy spare modules, just let me know what you have on hand. Thanks

It looks similar to the SP66 cutting console I have. In the SP66 the PEV's serve as the Line Input as well as the EQ. The PV46's are used as gain makeup for attenuators. The PV15's are Line Out.

This is how it's done on the 69 console too, so I assume my smaller console will be the same as well

I am planning to have only one stereo output, so I maybe will use the remaining PV-15 modules to set up some aux channels

What I would really like to do is using the PV-46 modules as both line and mic amplifiers, with a switch to select the input source

I am wondering if they would be good as mic preamps as well, I have report from other people who racked them up as mic pre, but no direct experience.

I guess the best thing to do would be starting doing experiments once the console has arrived !

Another thing I am unsure about, for expanding the channels I got some Eckmiller W85 faders. They are a different model and technology (resistor ladder instead of carbon track) but I don't have any datasheet regarding impedance, etc.. So I don't know how they will match to the faders in the console.

Anyone that knows something about this german treasures, Is more than welcomed to jump onboard

Stay tuned !

 

[beatnik]

I could find out that the W85 faders have an input/output impedance of 250 ohms, but I have no information regarding the MR90 faders that are in the console

 

[Gold]

The BSY 90 transistors can be difficult to source. PM me for a couple of leads if you need it.

If it was mine I would try to restore it to original condition first. It will sound fantastic. I used an SP66 tape machine console for about five years and it sounded fantastic. I now have a rack mount SP66 which will be paired with a second lathe I have. It's the only Neumann mastering console worth having IMO.

I think that 69 console may have been the one installed at A&R in NYC. I have original paper for a large format console from the Gotham library but I don't have those export documents. I was speaking with a household name engineer and he got all misty eyed when I showed him the picture. He said it was one of the best sounding consoles he ever used.

 

[beatnik]

Thanks for your help Paul

I am not thinking to modify it heavily, just add some more channels and a couple of aux buses. Maybe add a cigarette lighter as well. oh no wait, i've quit that shit

I was thinking to rip it completely and just scrap out the cards and modules, but I then decided that would be a shame to destroy such a nice little old desk

I think the 69 manual i posted comes from the Gotham archives, maybe we are talking about the same one

Stay tuned !

 

[gyraf]

These guys have some parts at decent prices: http://www.schmitronic.de/#{14}

 

[Gold]

I think the 69 manual i posted comes from the Gotham archives, maybe we are talking about the same one

I think the serial number for the console you posted is  0023-113. I'll see what I have says.

I tried for years to source an ashtray for the SP 75 console I used. I hated the SP75. Nowhere near as good sounding as the SP66 but had enough the facilities needed to use in a modern setup.

 

[beatnik]

These guys have some parts at decent prices: http://www.schmitronic.de/#{14}

That is a good shop, not just for this Neumann stuff, thanks for letting me know.

I hated the SP75. Nowhere near as good sounding as the SP66 but had enough the facilities needed to use in a modern setup.

Where you think the difference in sound quality came from ?

 

[Gold]

Where you think the difference in sound quality came from ?

The transfer path is okay on the SP75. It's an RV75 attenuator with OEV EQ and HT75 HPF/LPF. It uses the PV46D for the output. There are two versions of the PV46 with the OA10's. With and without transformers. The ones without transformers don't sound great. The ones with transformers sound cleaner. I don't know why.

The monitor section is the worst. It uses CMOS switching for source selection. They sound terrible. The overall of design of the console seems piecemeal. Some outputs are unbalanced and some are balanced. It's kind of like they looked around and used what they had laying around. There was also a summing circuit for reverb return which did not sound good.

 

[beatnik]

nice to hear your insight on that

i am curious to hear how the transistor based modules sound will compare to the opamp version

in about ten days i should be able to get the mixer

Stay tuned !